The present invention relates to a semiconductor device having a touch panel controller, a display driver and a processor, and further an electronic device having the semiconductor device used therein, and for example, a technique useful in application to a portable information terminal having, as an input device, a touch panel superposed on a liquid crystal panel.
A touch panel which supports a multipoint touch according to a mutual capacitance method has a plurality of drive electrodes and a plurality of detection electrodes, and mutual capacitances formed thereby. A finger or hand brought close to such a touch panel reduces a mutual capacitance between the electrodes near the finger or hand. To detect the position of the electrode where the mutual capacitance change is caused, the touch panel controller drives the drive electrodes sequentially by pulses, integrates, as a signal, a change in voltage developed on each of the detection electrodes capacitively coupling with the drive electrodes, and acquires, by positions between the electrodes, signals resulting from the integration for the respective detection electrodes.
U.S. Patent Application Publication No. 2007/0257890A1 describes this type of controller which drives a touch panel and detects signals according to the mutual capacitance method.